TYPE A1: No
sap, no black dots, no insects attack, smooth
and flat, no waving, no mineral line, easy
sticky, non glare, corrosion resistance, no special
smell.
TYPE A2: Slight discolor allowed, slight splits allowed,
no holes allowed.
TYPE B : Medium dislolor allowed, split
allowed, no holes allowed.
TYPE C
:Discolor allowed, splits allowed, within 2 holes
diametre below 1.5 cm allowed.